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Language	Haskell98

Options.Applicative.Extra

Contents

Extra parser utilities

Synopsis

helper :: Parser (a -> a)
hsubparser :: Mod CommandFields a -> Parser a
execParser :: ParserInfo a -> IO a
execParserMaybe :: ParserInfo a -> [String] -> Maybe a
customExecParser :: ParserPrefs -> ParserInfo a -> IO a
customExecParserMaybe :: ParserPrefs -> ParserInfo a -> [String] -> Maybe a
execParserPure :: ParserPrefs -> ParserInfo a -> [String] -> ParserResult a
getParseResult :: ParserResult a -> Maybe a
handleParseResult :: ParserResult a -> IO a
parserFailure :: ParserPrefs -> ParserInfo a -> ParseError -> [Context] -> ParserFailure ParserHelp
renderFailure :: ParserFailure ParserHelp -> String -> (String, ExitCode)
newtype ParserFailure h = ParserFailure {
- execFailure :: String -> (h, ExitCode, Int)
}
overFailure :: (ParserHelp -> ParserHelp) -> ParserResult a -> ParserResult a
data ParserResult a
- = Success a
- | Failure (ParserFailure ParserHelp)
- | CompletionInvoked CompletionResult
data ParserPrefs = ParserPrefs {
- prefMultiSuffix :: String
- prefDisambiguate :: Bool
- prefShowHelpOnError :: Bool
- prefShowHelpOnEmpty :: Bool
- prefBacktrack :: Backtracking
- prefColumns :: Int
- prefHelpLongEquals :: Bool
}
newtype CompletionResult = CompletionResult {
- execCompletion :: String -> IO String
}

Extra parser utilities

This module contains high-level functions to run parsers.

helper :: Parser (a -> a) Source #

A hidden "helper" option which always fails.

A common usage pattern is to apply this applicatively when creating a ParserInfo

opts :: ParserInfo Sample
opts = info (sample <**> helper) mempty

hsubparser :: Mod CommandFields a -> Parser a Source #

Builder for a command parser with a "helper" option attached. Used in the same way as subparser, but includes a "--help|-h" inside the subcommand.

execParser :: ParserInfo a -> IO a Source #

Run a program description.

Parse command line arguments. Display help text and exit if any parse error occurs.

execParserMaybe :: ParserInfo a -> [String] -> Maybe a Source #

Deprecated: Use execParserPure together with getParseResult instead

Run a program description in pure code.

This function behaves like execParser, but can be called from pure code. Note that, in case of errors, no message is displayed, and this function simply returns Nothing.

If you need to keep track of error messages, use execParserPure instead.

customExecParser :: ParserPrefs -> ParserInfo a -> IO a Source #

Run a program description with custom preferences.

customExecParserMaybe :: ParserPrefs -> ParserInfo a -> [String] -> Maybe a Source #

Deprecated: Use execParserPure together with getParseResult instead

Run a program description with custom preferences in pure code.

See execParserMaybe for details.

execParserPure Source #

Arguments

:: ParserPrefs	Global preferences for this parser
-> ParserInfo a	Description of the program to run
-> [String]	Program arguments
-> ParserResult a

The most general way to run a program description in pure code.

getParseResult :: ParserResult a -> Maybe a Source #

Extract the actual result from a ParserResult value.

This function returns Nothing in case of errors. Possible error messages or completion actions are simply discarded.

If you want to display error messages and invoke completion actions appropriately, use handleParseResult instead.

handleParseResult :: ParserResult a -> IO a Source #

Handle ParserResult.

parserFailure :: ParserPrefs -> ParserInfo a -> ParseError -> [Context] -> ParserFailure ParserHelp Source #

Generate a ParserFailure from a ParseError in a given Context.

This function can be used, for example, to show the help text for a parser:

handleParseResult . Failure $ parserFailure pprefs pinfo ShowHelpText mempty

renderFailure :: ParserFailure ParserHelp -> String -> (String, ExitCode) Source #

newtype ParserFailure h Source #

Constructors

ParserFailure
Fields execFailure :: String -> (h, ExitCode, Int)

Instances

Functor ParserFailure Source #
Instance details Defined in Options.Applicative.Types Methods fmap :: (a -> b) -> ParserFailure a -> ParserFailure b # (<$) :: a -> ParserFailure b -> ParserFailure a #
Show h => Show (ParserFailure h) Source #
Instance details Defined in Options.Applicative.Types Methods showsPrec :: Int -> ParserFailure h -> ShowS # show :: ParserFailure h -> String # showList :: [ParserFailure h] -> ShowS #

overFailure :: (ParserHelp -> ParserHelp) -> ParserResult a -> ParserResult a Source #

data ParserResult a Source #

Result of execParserPure.

Constructors

Success a
Failure (ParserFailure ParserHelp)
CompletionInvoked CompletionResult

Instances

Monad ParserResult Source #
Instance details Defined in Options.Applicative.Types Methods (>>=) :: ParserResult a -> (a -> ParserResult b) -> ParserResult b # (>>) :: ParserResult a -> ParserResult b -> ParserResult b # return :: a -> ParserResult a # fail :: String -> ParserResult a #
Functor ParserResult Source #
Instance details Defined in Options.Applicative.Types Methods fmap :: (a -> b) -> ParserResult a -> ParserResult b # (<$) :: a -> ParserResult b -> ParserResult a #
Applicative ParserResult Source #
Instance details Defined in Options.Applicative.Types Methods pure :: a -> ParserResult a # (<>) :: ParserResult (a -> b) -> ParserResult a -> ParserResult b # liftA2 :: (a -> b -> c) -> ParserResult a -> ParserResult b -> ParserResult c # (>) :: ParserResult a -> ParserResult b -> ParserResult b # (<*) :: ParserResult a -> ParserResult b -> ParserResult a #
Show a => Show (ParserResult a) Source #
Instance details Defined in Options.Applicative.Types Methods showsPrec :: Int -> ParserResult a -> ShowS # show :: ParserResult a -> String # showList :: [ParserResult a] -> ShowS #

data ParserPrefs Source #

Global preferences for a top-level Parser.

Constructors

ParserPrefs

Fields

prefMultiSuffix :: String
metavar suffix for multiple options
prefDisambiguate :: Bool
automatically disambiguate abbreviations (default: False)
prefShowHelpOnError :: Bool
always show help text on parse errors (default: False)
prefShowHelpOnEmpty :: Bool
show the help text for a command or subcommand if it fails with no input (default: False)
prefBacktrack :: Backtracking
backtrack to parent parser when a subcommand fails (default: Backtrack)
prefColumns :: Int
number of columns in the terminal, used to format the help page (default: 80)
prefHelpLongEquals :: Bool
when displaying long names in usage and help, use an '=' sign for long names, rather than a single space (default: False)

Instances

Eq ParserPrefs Source #
Instance details Defined in Options.Applicative.Types Methods (==) :: ParserPrefs -> ParserPrefs -> Bool # (/=) :: ParserPrefs -> ParserPrefs -> Bool #
Show ParserPrefs Source #
Instance details Defined in Options.Applicative.Types Methods showsPrec :: Int -> ParserPrefs -> ShowS # show :: ParserPrefs -> String # showList :: [ParserPrefs] -> ShowS #

newtype CompletionResult Source #

Constructors

CompletionResult
Fields execCompletion :: String -> IO String

Instances

Show CompletionResult Source #
Instance details Defined in Options.Applicative.Types Methods showsPrec :: Int -> CompletionResult -> ShowS # show :: CompletionResult -> String # showList :: [CompletionResult] -> ShowS #